The Grand Hybrid keyboard is literally taken from a C. Bechstein grand piano. Because of this, a keypress sends a hammer on the same path as a grand piano. Combined with the same weight and pivot points, this is as close as you can get to the real thing.

The GP400 uses the same speaker system as the 300, however the cabinet design is slightly larger. The music stand built into the unit is slightly higher, giving you a closer representation to playing a real Bechstein grand piano. Clever, subtle, and noticeable difference.